Drills, hammer drills and chippers are power tools that can operate in at least one of three modes of operation. Drills, hammer drills and chippers have a cutting tool such as a drill bit or chisel that can be operated in at least one of a hammering mode, a rotary mode and a combined hammer and rotary mode. Drills, hammer drills and chippers will typically comprises an electric motor and a transmission mechanism by which the rotary output of the electric motor rotationally drives the cutting tool and/or repetitively strikes the cutting tool to perform the hammer function. Such a transmission mechanism can be mounted within a transmission housing which is in turn mounted within an external housing of the hammer drill. The electric motor can be directly mounted onto the transmission housing. The use of such a transmission housing allows the transmission mechanism to be assembled within the transmission housing and the electric motor mounted onto the transmission housing with the rotary output of the electric motor being drivingly connected to the transmission mechanism to form a single sub-assembly which can then inserted into the external housing.
EP1674215 discloses a hammer drill capable of operating in all three modes of operation and which has a transmission mechanism mounted within a transmission housing and an electric motor mounted onto the transmission housing which are then mounted within an external housing.